Low positive temperature, has an inhibiting effect on growth, development and other physiological processes of cold-sensitive plants which include soybean. An experiment in Petri dishes investigated the effect of temperature: 28/28°C (control), 10/28°C, 28/10°C, and 10/10°C (imbibition/germination), on germination of seeds of 8 soybean cultivars. Another experiment, carried out using pot cultures, investigated the response of 2-week soybean plants of the same cultivars to a 6-day chilling period. The following temperatures were used: 25/20°C (control), 25/0°C, 10/0°C (day/night). Both experiments tested the response of 6 domestic soybean cultivars (‘Aldana’, ‘Jutro’, ‘Progres’, ‘Mazowia’, ‘Nawiko’, and ‘Augusta’) and 2 Canadian cultivars (‘OAC Vision’, ‘Dorothea’) to chilling. The obtained results showed that a temperature of 10°C used during germination (28/10°C), and even to a larger extent during imbibition and germination (10/10°C), clearly reduced the speed of germination, percentage of germinated seeds, and radicle length relative to the control, but it increased catalase activity in sprouts. A chilling temperature of 25/0°C and 10/0°C (day/night) significantly increased leaf electrolyte leakage, free proline content and catalase activity relative to the control, but it decreased the photosynthetic rate and total plant leaf area. Seeds and seedlings of cvs. ‘Jutro’ and ‘Nawiko’ were generally the least sensitive to chilling, while ‘Aldana’ and ‘Dorothea’ were the most sensitive.

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